When working on a requirements document, how do I capture system roles and responsibilities?
E.g. “I’m a manager and I will only use the system to generate reports on xyz”.
I was looking for an example online but couldn’t find one.
You may benefit from reading up on Agile Development Methodology. In this methodology requirements gathering is done in the form of “User Stories”. For example:
“As a manager I want to be able to generate reports on XYZ”
“As a customer I want to be able to see my recent transactions”
etc.
A proper use case should clearly state the Actors involved.
In your case “Manager” is the actor in a “Manager receives daily reports” use case.
Also note that use case Actors just like actors in a theater company may have several roles.
So “Manager” is also an “Employee” and perhaps a “C.C. for CIO”.